Add new AI agent for managing menus and menu items

Changes have been added to the relevant branch — please pull the latest code and test as follows:

How to test the Menu Agent

1. Install the Drupal CMS AI recipe → .
2. Check out the code from the branch containing the Menu Agent implementation.
3. Run the database updates to register the new agent configuration:
   drush updb
4. Go to the AI Assistant configuration page and edit Drupal CMS Assistant settings.
5. Under "Agents Enabled", enable the Menu Agent by checking the corresponding checkbox.
6. Open the Drupal Agent Chatbot prompt.
7. Try creating or editing menus and menu links using natural language commands (e.g., "Create a new menu called Books Menu", or "Add a home page link to the Footer menu with title Home").

Great work! @Sijumpk. I have reviewed and the menu agent is working fine. Only thing is you no need to specify to install drupal cms in steps to reproduce, we can test in drupal core as well.
Steps followed:

1. Run the database updates to register the new agent configuration:
2. drush updb
3. Edit the AI Assistant configuration settings.
4. Under "Agents Enabled", enable the Menu Agent by checking the corresponding checkbox.
5. Open the Drupal Agent Chatbot prompt.
6. Tried creating or editing menus and menu links using natural language commands (e.g., "Create a menu Cities with terms as metro cities in India", "You can add Delhi, Chennai, kochi, Bangalore, Mumbai", Add a home page link to the Footer menu with title Home").

Cities menu got created and terms where added. Home page link to the Footer menu with title Home was added.

SS attached

Yes, Anjali, I specified the Drupal CMS AI recipe just to make the testing setup easier. Essentially, it’s simply another agent—like ContentType, FieldType, or TaxonomyAgent—that can be used for regular agentic purposes.